It is oftentimes necessary to recover materials from aqueous solutions such as water. With respect materials in solid form that are suspended in the aqueous solution, such materials can be collected by a common filtration process by passing the liquid through a filter having suitable small apertures therein. But such a process cannot recover materials in the aqueous solution that are dissolved in the solution. While failure to recover dissolved materials might not be critical in some instances, it is important, and often vital, in other instances.
It is often important, for example, to determine the elements present in water since water is a basic part of our environment. In this regard, trace impurities in water are an important factor in the growth of people, animals and plants, and accurate measurements of impurities in water can avoid health hazards which are already known and can be utilized to determine unknown correlations between trace elements and healthy growth.
By way of further example, water flows over and through much of the earth. During this flow, minerals are dissolved in the water. Information for locating such minerals (including valuable minerals) can be obtained by recovering and analyzing these trace impurities.
In both of the foregoing examples, impurities as small as one part per billion parts of water can be significant. It is therefore obvious what accurate measurement cannot be achieved if there is appreciable loss in recovery of the materials or if introduction of extraneous matter is not minimized.
Thus, a recovery system that recovers as many elements as possible will provide the best and most accurate information. In addition, such a system should, if possible, be simple yet dependable and be economical to operate.
While dissolved materials cannot be recovered by the common filtration system described hereinabove, it is, of course, possible to precipitate some of the dissolved materials by adding appropriate chemicals. This process, however, has been found to be disadvantageous in recovering all original materials in the liquid without loss or addition of unknown trace impurities.